The present invention relates to pyrimidine derivatives, and more particularly to novel crystalline salts of (E)-7-[4-(4-fluorophenyl)-6-isopropyl-2-[methyl(methylsulfonyl)amino]pyrimidin-5-yl]-(3R,5S)-3,5-dihydroxyhept-6-enoic acid of the formula
which are useful as inhibitors of the enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG CoA reductase) and as intermediates in the manufacture of, for example, the non-crystalline calcium salt of (E)-7-[4-(4-fluorophenyl)-6-isopropyl-2-[methyl(methylsulfonyl)amino]pyrimnidin-5-yl]-(3R,5S)-3,5-dihydroxyhept-6-enoic acid of the formula

The invention also concerns pharmaceutical compositions which include the crystalline salts, as well as processes for the manufacture of the crystalline salts. The invention further concerns methods of treating medical conditions in which HMG CoA reductase is implicated using the crystalline salts, for example hyperlipidemia, hypercholesterolemia and atherosclerosis, and the use of the crystalline salts in the manufacture of a medicament. The invention further concerns the use of the crystalline salts in the manufacture of the non-crystalline calcium salt of (E)-7-[4-(4-fluorophenyl)-6-isopropyl-2-[methyl(methylsulfonyl)amino]pyrimidin-5-yl]-(3R,5S)-3,5-dihydroxyhept-6-enoic acid.
European Patent Application, Publication No. 521471 (hereinafter EPA 521471), discloses an amorphous (powder) form of the calcium salt of (E)-7-[4-(4-fluorophenyl)-6-isopropyl-2-[methyl(methylsulfonyl)amino]pyrimidin-5-yl]-(3R,5S)-3,5-dihydroxyhept-6-enoic acid, and the sodium salt is obtained therein as “powdery crystals”. These salts are HMG CoA reductase inhibitors and the calcium salt is undergoing clinical trials.
A powdery or amorphous form of a compound intended for pharmaceutical use may give rise to manufacturing problems and there is therefore a need to identify alternative salts of (E)-7-[4-(4-fluorophenyl)-6-isopropyl-2-[methyl(methylsulfonyl)amino]pyrimidin-5-yl]-(3R,5S)-3,5-dihydroxyhept-6-enoic acid which are crystalline. Such crystalline salts can generally be purified more easily than an amorphous form and may possess other advantageous properties. A difficulty is also experienced in obtaining pure amorphous calcium salt using the procedure disclosed in EPA 521471, because of the difficulty in purification of the precursor sodium salt arising from its physical form. A further feature of the crystalline salts is that they can also advantageously be used as intermediates in the manufacture of the non-crystalline calcium salt, to enable isolation of non-crystalline calcium salt with a purity level and uniformity suitable for formulation to meet exacting pharmaceutical requirements and specifications.